Risk Genetic Assessment and Genetic Counseling Research
John Quillin Human Genetics Virginia Commonwealth University
Outline for today
Of Risk and Popcorn Cancer Risk Factors Genetic Risk Assessment Implications for Cancer Control Genetic Counseling Research
1
Of Risk and Popcorn
Of Risk and Popcorn
250 200
# of Pops
150
100
50
0
0 to 0.5 0.5 to 1 1 to 1.5 1.5 to 2 2 to 2.5 2.5 to 3 3 to 3.5 3.5 to 4 4 to 4.5
Minutes
2
Of Risk and Popcorn
250 200
# of Pops
N = 250 (per bag)
150
100
50
0
0 to 0.5 0.5 to 1 1 to 1.5 1.5 to 2 2 to 2.5 2.5 to 3 3 to 3.5 3.5 to 4 4 to 4.5
Minutes
Of Risk and Popcorn
250 200
Cumulative Risk
# of Pops
N = 250 (per bag)
150
100
50
0
0 to 0.5 0.5 to 1 1 to 1.5 1.5 to 2 2 to 2.5 2.5 to 3 3 to 3.5 3.5 to 4 4 to 4.5
Minutes
3
What determines if a kernal pops?
External factors
How long its in the microwave The type of microwave Oil/seasonings
Internal factors
Genes (genetically-modified corn??) Soil/nutrients
Breast Cancer Risk
# per 250 with Breast
250 200
Cancer
150
100
50
0
0 to 20 20 to 40 40 to 60 60 to 80 80 to 95+
Years
4
What affects cancer risk?
Diet Tobacco Hereditary Occupation Radiation Viruses Other
Sporadic
Familial
Mendelian
5
Family History and Chance of Breast Cancer
100
Number with Breast Cancer out of 100 Women
90 80 70 60 50 40 30 Two Paternal Aunts 20 10 0 Mother Mother and Maternal Aunt Mother and Sister
Mother
Two Paternal Aunts
Mother and Maternal Aunt
Mother and Sister
Family History
Claus, 1990
Twin Studies
Breast Cancer in Twins
100% 90%
Percent Each Within Group
80% 70% 60% 50% 40% 30% 20% 10% 0%
One Has Cancer Both Have Cancer
Identical Twins
Fraternal Twins
N Engl J Med 2000;343:78-85
6
Causes of Breast Cancer
27%
6% 67%
Genetics
Shared Environment
Unique Environment
BRCA1 and BRCA2
Science 2003;302(5645):643-6
7
More likely to be hereditary if
Earlier-than-expected age of onset Multiple primary cancers Rare cancers Inheritance pattern Syndrome (malignant and non-malignant characteristics) No clear environmental association
Peutz-Jeghers Syndrome
8
Cancer Control Implications
Primary prevention
Medication (e.g., tamoxifen, sulindac) Risk-reducing surgery Lifestyle (e.g., exercise) Diet (coffee??)
Secondary prevention
Timing (age of initiation, interval) Method (MRI) Whether or not to screen at all
Cancer Control Implications
Tertiary prevention
Chemotherapy Extent of surgery Radiation
9
Why genetic counseling?
Risk communication...